Fin
The finished product:
The only holes I cut in the case:
Once I enabled the bios option to power on via the spacebar I don't even have to crack the case unless I need to use the optical drive. As this doesn't happen very often I'm quite pleased with how this worked out. I ran a stress test (cpustabtest.exe works the CPU hard in an effort to max out the thermal envelope) while running a defrag and scandisk of separate partitions on the HDD (I could sacrifice the OS install if the machine hung during the stress test) and the max temp of the CPU stabilized at 69 degrees after about 20 minutes and stayed there for 40 minutes until I called off the test. That's a little hot but it was perfectly stable and I'm not really worried about it. If the opportunity presents itself I'll install a better heatsink with more fins but the fit will be tight between the socket and the ducted fan mounted from the lid directly above it. It's not as quiet as I'd like as the CPU fan was repurposed to draw air in from the expansion card slots upstream of the video card and it is no longer speed controlled by the motherboard. Air is also directed by the GPU fan towards the power supply. The power supply fan pulls air through itself before being forced up along the case wall and back over the HDD (mounted under the the optical drive). Finally the air gets a chance to exit the case via the CPU heatsink and associated fan duct. It's a very effective solution but I think I'll source a quiet fan (another SilentX there would bring the installed total to 3) and then I'll be much happier keeping the case on my desk where I can see it but not hear it :).
A great stealth solution. Can't wait for the next LAN party.